1. Field of the Invention
This invention relates to endotracheal tubes. More particularly, this invention relates to devices for indicating the degree of inflation of the cuff of the endotracheal tube when positioned within the trachea of a patient.
2. Description of Prior Art
An endotracheal tube is used during surgical procedures and in emergency situations rather than performing a tracheostomy. Conventional endotracheal tubes consist of a piece of tubing, approximately one foot in length, which has an inflatable, balloon-like device known as a cuff at its terminal end. An air inflation cuff channel is formed within the wall of the tube and opens at its terminal end within the cuff to permit inflation of the same. A small bore cuff tube is sealingly connected to the cuff channel. A valve is fitted to the end of the cuff tube allowing a conventional syringe to inflate the cuff via the cuff tube and cuff channel.
During intubation, the patient's epiglottis is pulled back with a laryngoscope and the endotracheal tube is then inserted past the epiglottis, through the vocal chords, and then into the trachea of the patient, thereby positioning the cuff of the endotracheal tube below the vocal chords and above the bronchial tubes of the patient. While holding the endotracheal tube in position, the laryngoscope is removed. The tube is then secured in place by adhesive strapping. A bite block is placed in the patient's mouth to prevent the biting of the endotracheal tube.
The cuff is inflated by affixing a syringe to the valve at the end of the cuff tube and then operating the syringe to pump air into the cuff via the cuff tube and cuff channel. Two or three pumping operations are usually necessary in order to properly inflate the cuff and provide a proper seal between the lumen of the patient's trachea and the endotracheal cuff.
Endotracheal tubes are universally used because of the many advantages over a tracheotomy. More particularly, the use of an endotracheal tube allows the passage of anesthetic and analgetic gases into the lungs and the removal of carbon dioxide. With a properly inflated cuff, a "gas-tight" endotracheal anesthesia is assured and the collection of large amounts of carbon dioxide is avoided. In addition to administering anesthetic and analgetic gases, the endotracheal tube provides a passageway for a suction catheter to be inserted into the trachea to remove any accumulation of mucus in the lung tissue, thereby significantly reducing the possibility of infection and resulting pneumonia. Finally, the endotracheal tube prevents passage of mucus, blood, saliva, irrigants, vomitus, etc. into the trachea and the lungs during a surgical procedure.
Obviously, the foregoing advantages of using an endotracheal tube cannot be accomplished if the cuff is not properly inflated to adequately seal the space between the lumen of the trachea and the cuff of the endotracheal tube itself. Accordingly, there is a tendency to over-inflate the cuff to assure that such a proper seal has been formed between the lumen of the trachea and the cuff. Unfortunately, over- or excessive inflation of the cuff beyond the point which is necessary for a proper seal results in necrosis or damage to the lumen of the trachea.
One attempt to overcome the tendency to over-inflate the cuff has been to provide a balloon or bulb in-line with the cuff supply tube. Inflation of the endotracheal cuff causes the bulb to also inflate. The anesthetist then tactilely tests the bulb between his/her forefinger and thumb to obtain an indication of the degree of inflation of the cuff itself. Obviously, this is a subjective procedure which depends on the anesthetist's ability to feel the pressure in the bulb and correlate the same to the degree of inflation of the cuff in the patient's trachea. While this bulb device is used almost universally, its limitation are apparent, particularly when used by less experienced anesthetists.
Recently, there has been developed a caged balloon or bulb which is designed to be affixed to the end of the cuff supply tube. The caged bulb consists of a thin-walled bulb which is positioned within a rigid cage. Similar to conventional bulbs, as the endotracheal cuff is inflated, the thin-walled, caged bulb is also inflated. The openings of the cage allow the anesthetist to tactilely test the degree of the inflation of the bulb. Upon over-inflation of the cuff, the bulb protrudes from the cage via the openings. A more complete disclosure of this device can be found in U.S. Pat. No. 4,134,407, the disclosure of which is hereby incorporated by reference herein.
The caged bulb described above has not been widely used in the industry. Primarily, this is because it operates substantially identically to the conventional non-caged bulb and, therefore, suffers the same disadvantages of permitting only a subjective determination of the air pressure in the endotracheal cuff. Further, the structure of the caged bulb is difficult to manufacture on a production basis and, therefore, extremely costly.
Therefore, it is an object of this invention to provide an apparatus which overcomes the aforementioned inadequacies of the prior art devices and provides an improvement which is a significant contribution to the advancement of the endotracheal tube art.
Another object of this invention is to provide a means for objectively indicating when the cuff of an endotracheal tube has been inflated to properly seal the space between the lumen of a trachea and the wall of the cuff.
Another object of this invention is to provide an indicator for objectively indicating the degree of inflation of the cuff of an endotracheal tube to assure proper inflation of the cuff during use.
Another object of this invention is to provide an indicator for an endotracheal cuff which can be used in conjunction with conventional endotracheal tubes without requiring alteration of the tube itself.
Another object of this invention is to provide an indicator for endotracheal cuffs having a simple and reliable construction which can be manufactured in production quantities at relatively low cost.
Another object of this invention is to provide an endotracheal cuff indicator having an indicating diaphragm which visually and objectively indicates to the anesthetist the degree of inflation of the endotracheal cuff.
Another object of this invention is to provide an indicator for an endotracheal cuff which is manufactured in conjunction with a syringe-operable, one-way valve which permits a conventional syringe to be fitted thereto and pumped to inflate the endotracheal cuff via the cuff tube and cuff channel and then removed from the valve whereupon the valve closes to prevent leakage of the air from the cuff.
The foregoing has outlined some of the more pertinent objects of the invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the intended invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the summary of the invention and the detailed description of the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.